PVC heat stabilizers affect the transparency of several factors

1, the refractive index of the stabilizer
PVC resin, heat stabilizer and 1.52 to 1.55 of the refractive index of the visible light are the  chromium oxide same or similar, then the better the transparency of PVC products, the transparency is low and vice versa.
2, stabilizer molecules (molecules) of linear length
Heat stabilizer molecule (or molecules) linear length is less than 400 ~ 735nm wavelength of visible light refracting fewer higher degree of transparency, whereas less transparent.
3, a heat stabilizer in PVC, "solubility", ie compatibility
The so-called compatibility of two or more substances refers to the mutual affinity when mixed. Good compatibility is possible to achieve dispersion of the molecular level. Thermal stabilizer in the PVC stabilizer for pipe  molten state has good compatibility with PVC resin. Do not form a two-phase, that is no interface or the interface is not obvious, less refracted light, PVC products, higher transparency. Liquid stabilizer than the corresponding solid metal soap good compatibility in PVC, the linear molecule has a smaller length, and thus the higher the transparency of the PVC.